The 3GPP (3rd Generation Partnership Project) which is a mobile communication system standardization project is planning to promote the standardization of CoMP (Coordinated Multi-Point) in the release 11 or later (see, non-patent document 1).
In the CoMP, a group of antennas installed in the same place is regarded as a “point,” and multiple points cooperatively perform communication with a user terminal. The group of points performing cooperative communication with the user terminal using one time-frequency resource is referred to as a CoMP cooperating set.
As one category of CoMP, there is joint processing (JP) in which data to be communicated to a user terminal is available at multiple points in a CoMP cooperating set.
In addition, as one category of JP in uplink, there is JR (Joint Reception) in which multiple points in a CoMP cooperating set jointly receive the same data from a user terminal.
In the case of JR-type CoMP in which a CoMP cooperating set is formed by different base stations, a conceivable way to combine data received at the respective base stations from the user terminal together is as follows.
To be more specific, the CoMP cooperating set includes a main base station and at least one subordinate base station. Each subordinate base station transfers data received from the user terminal to the main base station, and the main base station combines the data received by the main base station itself, and the data received by the respective subordinate base stations. Then, the main base station transmits the combined data to the core network.